WO1988008500A1

WO1988008500A1 - A method and means for providing a thermic insulating effect around an article, such as a pipeline which is submerged in water

Info

Publication number: WO1988008500A1
Application number: PCT/NO1988/000033
Authority: WO
Inventors: Dag Vilnes
Original assignee: Dag Vilnes
Priority date: 1987-04-29
Filing date: 1988-04-28
Publication date: 1988-11-03
Also published as: EP0312566A1; NO871795L; NO163648C; NO871795D0; AU1689188A; BR8806990A; US4913588A; NO163648B

Abstract

A method and means for insulating a pipeline (1) which is more or less submerged in the sea bottom consists in that the insulation (3) is made directly at the pipeline (1). The substances for production of the insulating covering are transported to a mixing chamber (7) at the production site and are foamed around the pipeline (1). For this purpose may be used a flexible sheet (4) of material such as foil which is anchored to the sea bottom (2). Through the production of the insulation (3) in situ, the gas pressure in the insulating material (3) can be adapted to the outer pressure and thereby a compression of the material with loss of insulating effect can be avoided.

Description

A method and means tor providing a thermic insulating effect around and article, such as a pipe line which is submerged in water

The invention relates to a method tor providing a thermic insulating ettect around an article, such as pipe line which is submerged in water, by the use of a toam based insulating substance. The invention also relates to means tor use in providing such a thermic insulating covering over an article.

Especially, the invention is intended tor use in connection with pipe lines tor transport of liquids and gases, such as hydrocarbon products trom submerged wells positioned on the sea bottom in very deep water.

During transport of hydrocarbons in production pipe lines, there will take place a considerable cooling which will cause a reduction ot the pressure and increased viscosity with resulting demand tor pumping capacity and separating capacity. It is therefore wanted to insulate such pipe .lines. A problem in this connection will however be that the outer pressure in deep water will be very high and that the insulating material will be exerted tor an outer pressure which will reduce the gas volume in the insulating material and thereby also the insulating properties ot the material.

The ob ect of the present invention is to avoid this problem. This object is achieved by a method as described in the patent claims.

The invention also relates to means tor use in the production ot thermic insulating coverings in deep water, i.e. by high outer pressure. A means tor such use is characterized by the features given in the means claims.

The present invention is based on the principle that the separate components which are necessary to produce the insulating material are brought separately down to the article which shall be insulated and that the material, for instance a cellular plastic material is produced in situ on or near the article or with other words at the place in which the production takes place and at the same pressure at which it shall be used. The components necessary tor producing a cellular plastic material in the torm ot toam are a gas with a pressure adapted to the outer pressure and solid substances such as a adhesives and foaming liquid.

The inventor has by tests prooved that it is possible to produce cellular plastic material under water and thereby achieve a product with good properties tor the intended purpose. Thus, a cellular plastic material based on amino- plastic has been produced under water by iorming of an aquous emulsion with air by the use ot conventional, acid forming agents and hardener. The cellular plastic material which was achieved was consolidated to a large unitary body with good insulating and adhesive properties and with sutticient mechanical strength.

The invention will in the following be further illustrated by means ot a possible embodiment which schematicly has been shown on the drawing. The tigures are showing:

Fig. 1 an isometric view illustrating a means according to the invention tor providing an insulating covering on the pipe line by the use ot the method according to the invention, and

tig. 2 a cross-section ot an insulated pipe, and

tig. 3 a detailed view of the toam producer and nozzle arrangement, and

tig. 4 a detailed view ot the torm element.

In the drawing it is shown an embodiment ot the invention, used tor insulating a pipe line 1 positioned at the sea bottom 2, partly submerged into the sea bottom. In order to insulate this pipe line 1 a covering of insulating foam 3 shall be produced around that part ot the pipe line which is positioned over the sea bottom 2. This toam is produced in the space between the pipe line 1 and a cap in the torm ot a flexible sheet material, which is wound oft trom a supply roll ^c . The foam producing substances are led to a toam producing or mixing chamber 7 through a supply and conduit system which generally has been referred to by 6 and which is ot known art. The agents which are transported to the toam producing chamber 7 may be air from a compresser and appropriate substances led in separate conduits and pumped tor instance with a two-component pump. These substances are mixed in the mixing chamber 7 and led out between the toil 4 and the pipe line 1 through an injection nozzle 8.

In order to protect the foam material the toil which acts as a torm may be anchored into the sea bottom as illustrated on tig. 2. Trench ploughs are moved along the pipe line, one on each side and are digging a recess in which the side edges ot the toil may be placed. Thereby the side edges are folded as illustrated by 13. After having placed the toil in the trenches a back-fill plough 14 are replacing the material which has been ploughed away and thereby anchoring the toil. Another possibility would be not to use ploughs but instead position some type of weight material on the side edges of the toil.

In order to regulate the thickness of the insulating layer, the first part ot the toil behind the injection site may be covered by a torm eiemet 10 ot a rigid material. In order to assist in bringing the toil material 4 to the pipe line this torm may have a tlared part 11 at the tront. In order to avoid toam from being pushed in a wrong direction it may be placed a tightening flap or element 9 in the aera at the tlared part 11 of the form element. The production of the insulating covering is made continuously by moving the production means along the pipe line. The devices tor moving has not been shown and neither has the rack elements tor fixing the different elements ot the means. The construction ot such elements will be self-evident tor the man skilled in the art and has therefore not been shown. Such elements can be positioned on the drive wells of a robot device or the like.

Claims

PATENT CLAIMS

1. A metod tor providng a thermic insulating effect around an article, such as a pipe line which is submerged in water, by the use of a foam based insulating substance, c h a r a c t e r i z e d i n that one or more toam materials are produced in situ or near the article which shall become insulatedT

2. A method according to claim 1, c h a r a c t e r i z e d i n that the toam material is injected into a cap surrounding the article and which is anchored to the sea bottom.

3. A method according to claim 1 or 2, c h a r a c t e. r i z e d i n that a torm is provided over the article or the cap in order to regulate the thickness ot the toam.

4. A method according to claim 2, c h a r a c t e r i z e d i n that a flexible sheet material is wound oft trom a supply, positioned over the article and that the longitudinal side edges thereof are provided with a weigth material, for instance by digging into the sea bottom.

5. A method according to claim 1, c h a r a c t e r i z e d i n that a cellular plastic material is produced in situ around the article.

6. A method according to claim 5, c h a r a c t e r i z e d i n that the cellular plastic material is produced on basis ot an aminoplastic, such as urea-formaledhyde and a gas and/or liquid, such as air or water.

7. A method according to claim 6, c h a r a c t e r i z e d i n that the aminoplastic as an aquous emulsion is led down to the article and is toamed there by the use ot gas or liquid, the emulsion and the gas/liquid being transported through separate conduits and the necessary, known additives tor stabilizing the cellular plastic being added through a further separate conduit.

8. A method according to claim 1, c h a r a c t e r i z e d i n that the production ot the toam material is made continuously by moving the production site along the article, preferably in length direction ot the article.

9. Means tor use in providing a thermic insulating covering of an article such as a pipe line submerged in water, whereby the insulating covering is produced in situ at or near the article between a cap material and the article, said means comprising supply devices tor the cap material which is to be distributed over the article, devices tor supplying the foaming agents additives, foaming gas or liquids, a mixing chamber and an injection nozzle tor said agents, a torm surrounding the cap material in the area ot injection ot the foaming agents, a closing element at the nozzle and means tor moving the means forwards during use.

10. Means according to claim 9, c h a r a c t e r i z e d i n that the torm has been provided with a tlared position at its forward end.